1. Field of the Invention
The invention relates generally to computer equipment and more particularly to devices and methods for entering full character sets of English, Greek, Chinese, Japanese and others with a numeric keypad common to telephones, calculators, etc.
2. Description of the Prior Art
When both the space and cost of a full alphanumeric keyboard can be accommodated in a computer system or instrument, each key can be dedicated to a particular character. Standard personal computer keyboards for English therefore feature individual keys for numbers 0-9, letters A-Z and a-z, punctuation and arithmetic operators. Keyboards provided for Japanese, for example, would be completely unwieldy because Japanese writing requires the use of Romanji (English Roman characters), Hiragana (Japanese phonetics), Katakana (foreign words in the Japanese phonetic set), and Kanji (fifth-century Chinese). Each of the Romanji, Hiragana and Katakana average twenty-six discrete characters, but even a simple set of Kanji characters can run into the thousands. So some computer systems permit entry of Japanese phonetics using Romanji, e.g., "m-a", "m-i", "m-u", "m-e", "m-o", etc. The user can then choose the Hiragana, Katakana, or Kanji sound-alike, e.g., , , , , , for Hiragana; and , , , , , for Katakana, respectively. The Kanji has several Chinese characters for each sound, all with very different meanings, so a list of the synonyms is usually presented on the screen for the user to select the one having the intended meaning.
Keyboards that come with a fixed set of characters each printed on a key button typically require a large number of keys to accommodate a rich character set for any particular language and alphabet. Such keyboards are, by definition, inflexible. Other languages and alphabets require hardware changes, and/or data entry method changes to accommodate large character sets, e.g., as required in written Japanese or Chinese.